[zeromq-dev] Trouble using ZMQ Ventilator/Worker/Sink paradigm with Python & C++

[Kiran Karra]

Hi All,

I am trying to replicate the ventilator/workers/sink paradigm described in
the ZMQ guide.  I have the same Python Ventilator, the same C++ worker as,
and the same Python Sink as was described in the ZMQ examples.  I want to
launch the ventilator, workers, and sink from one main python script, so I
created "class" wrappers around the ventilator & sink, and both of those
classes subclass the Python module "multiprocessing.Process."  Since the
C++ is a binary, I launch it with Python's subprocess.Popen call.

The order of starting all of this up is as follows:
h = subprocess.Popen('test')
time.sleep(1)
s = sinkObj.start()
time.sleep(1)
v = ventObj.start()

What I am finding is that no data is getting through the system when I
start up the components like this.  However, if I start the C++ binary in
its own shell, and only start the sinkObj and ventObj from the main python
script, it works fine.

I apologize in advance if this is more of a Python question than a ZMQ
question, but I haven't run into issues like this w/ Python's subprocess.
 I have also tried using os.system() instead of the subprocess... but same
issue.  I put all the code on this website:
https://github.com/kkarrancsu/zmqtest

Explanation of code files:
Ventilator.py --> the ventilator code from the ZMQ guide converted to a
"class"
Sink.py --> the sink code from the ZMQ guide converted to a "class"
test.cpp --> the C++ worker code from the ZMQ guide
Makefile --> to make the test.cpp
All.py --> file which attempts to run the workers, ventilator, and sink
from one main file

Again, sorry if this is a python question, but not sure who to get help
from here .. Thank you very much.

Kiran
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